Degenerative changes of the temporomandibular joint. Relationship to ethnicity, sex and occlusal supporting zones based on a skull material

Modifications of the articular eminence inclination in association with the loss of occlusal support in the molar area. A cone-beam computed tomography study

The articular eminence (AE) is part of the temporal component of the temporomandibular joint (TMJ). The inclination of the AE (AEI) has an important role in TMJ biodynamics, influencing the path of movement of the disc-condyle complex. Although AEI values might change due to tooth loss, little is known about what effect could have the loss of occlusal support in the molar area on AE morphology. AEI was measured on cone-beam computed tomography (CBCT) images of 41 patients (82 TMJs) with or without occlusal support in the molar region. The patients included in this study were divided into four groups: (1) patients with maintained occlusal support in the molar areas on both sides (right and left side) (MM); (2) patients with loss of occlusal support in the molar areas on both sides (right and left side) (LL); (3) patients with loss of occlusal support in the molar area only on the right side, but with maintained occlusal support on the left molar area (LM); (4) patients with loss of occlusal support in the molar area only on the left side, but with maintained occlusal support in the right molar area (ML). AEI values were higher in the TMJs on the side with maintained occlusal support in the molar area (M) than the AEI values measured in TMJs from the side with loss of occlusal support in the molar area (L). AEI values on the right side were higher in the MM patients in comparison to the AEI values on the right side of LL patients. The loss of occlusal support in the molar areas changes the mandibular biodynamics, which might be reflected in the morphological changes at the AE level, where it might cause flattening of the articular slope predominantly on the right side.

Prevalence and correlation with sex, age, and dental status of bone apposition at the mandibular angle and radiographic alterations of the temporomandibular joints: a retrospective observational study in an adult Swiss population

BACKGROUND

The purpose of this study was to determine the prevalence of radiographic changes in the mandibular angle (bone apposition) and osseous alterations in the temporomandibular joints (TMJs) in the adult population of Switzerland. In addition, the study intended to investigate possible correlations between the two sites of contour bone changes (mandibular angle and TMJ) and to analyze various patient-related factors, including sex, age, dental status, and medical history.

METHODS

Panoramic radiographs of 600 patients distributed into six age groups (283 females, 317 males, aged 20 to 79 years) were included to evaluate radiographic changes. The bone in the mandibular angle region and the shape of the condylar heads were examined for contour changes (bone apposition at the jaw angles and osseous changes of the TMJs). General estimating equations, binormal tests, and chi-squared tests were used for statistical analysis.

RESULTS

Approximately half of the mandibular angles (47.8%) showed bone apposition, mostly bilateral. TMJ alterations were less common (27%), often unilateral, with flattening being the most frequent finding. No significant correlation was found between the two sites. Bone apposition at the mandibular angle showed a significant male predominance, whereas TMJ changes did not differ by sex. Alterations in both sites increased with age, and were not related to dental status or analgesic use.

CONCLUSIONS

Bone apposition at the mandibular angle should be interpreted as part of the natural functional adaptation of the bone associated with aging. Assuming that parafunctional habits may influence the development and progression of alterations in the mandibular angle or TMJs, the presence of radiographic changes in these areas should prompt dental clinicians to investigate further in this direction.

TRIAL REGISTRATION

The study was approved by the Swiss Association of Research Ethics Committees (swissethics), BASEC reference number: 2020-00963 (25.05.2020).

Influence of edentulism on the structure and function of temporomandibular joint

Background

With the acceleration of the aging process of the population, the number of edentulous patients continuously increased. Edentulism induces the loss of occlusal relationship and cause adverse effects on the stomatognathic system. Temporomandibular joint (TMJ), as a significant component of this system, may also be affected by edentulism in the process of supporting mandibular movement.

Purpose

Provide a comprehensive review of the structure and function of TMJ in the edentulous population, as well as the prevalence of temporomandibular joint disorder (TMD) in edentulous group.

Study selection

An electronic search was conducted on articles prior to December 2022 to filter all papers relevant to the structure and function of TMJ in edentulous population. The internet databases (PubMed, Cochrane Library, Embase) were searched using various combinations of keywords for "edentulism" or "edentulous" and "TMJ" or "TMD".

Results

Firstly, 522 articles were selected from the internet database, and finally, a total of 44 articles met the inclusion and exclusion criteria. The research content of these articles mainly focuses on the structure and function of TMJ in edentulous patients, as well as the clinical signs and symptoms of TMD.

Conclusions

Edentulous arch induces the loss of occlusal relationship, which may lead to degenerative changes of TMJ components consisting of changes in morphology and bone mass density of condyle, articular fossa, and articular eminence. In addition, the condyle could be shifted backward and upward, and displacement of the articular disc may occur after dentition loss. And the condyle and the articular disc may be guided back to the normal position after effective prosthodontic treatment. But the conclusions of the study on the function of TMJ and the prevalence of TMD in edentulous people are inconsistent. The condition of TMJ, especially the position of condyle-fossa and the symptoms and signs of TMD should not be ignored. If necessary, radiographic examinations should be performed.

Factors influencing the articular eminence of the temporomandibular joint (Review)

The temporomandibular joint (TMJ), the most complex and evolved joint in humans, presents two articular surfaces: the condyle of the mandible and the articular eminence (AE) of the temporal bone. AE is the anterior root of the zygomatic process of the temporal bone and has an anterior and a posterior slope, the latter being also known as the articular surface. AE is utterly important in the biomechanics of the TMJ, as the mandibular condyle slides along the posterior slope of the AE while the mandible moves. The aim of this review was to assess significant factors influencing the inclination of the AE, especially modifications caused by aging, biological sex or edentulism. Studies have reported variations in the angles of the slopes of the AE between medieval and recent human dry skulls, as well as between subjects of different racial origin. Recent articles have emphasized the significant role that tooth loss has on the flattening of the AE. Although some papers have described biological sex or age as factors which could be associated with differences in AE angulations, edentulism seems to be a significant factor impacting on the inclination of the AE.

Prevalence of TMD among Children Provided with Fixed Orthodontic Treatment

Background

According to available scientific references and textbooks, there are contradictory views concerning the etiology of signs and symptoms of TMD.

Objectives

The aim of this study was to determine a correlation between the incidence of signs and symptoms of TMD in children aged 12-18 who do not wear a fixed orthodontic appliance and the incidence of signs and symptoms of TMD in children who wear a fixed orthodontic appliance.

Material and Methods

The total number of 120 subjects were included in this survey and divided into two groups. There were 60 respondents in the experimental group that consisted of 30 boys and 30 girls with different types of malocclusion, who were treated with a fixed orthodontic straight wire technique. The remaining 60 respondents, which was a group that also consisted of 30 boys and 30 girls, were patients with neutroclusion.

Results

The results of the study have shown that the TMJ clicking sound symptom, the most common symptom of TMD, occurs with almost equal prevalence in both groups of respondents; specifically, 56.4% in orthodontic patients, and 46.6% in the control group respondents. A statistically significantly higher percentage of female respondents in both groups have experienced headache problems (p <0.03).

Conclusion

On the basis of the statistics obtained as a result of this research, we can come to the conclusion that there is no correlation between the fixed orthodontic treatment and the development of signs and symptoms of TMD.

Temporomandibular arthropathies: A retrospective study with histopathological characteristics

Background

To investigate the incidence of temporomandibular arthropathies diagnosed in a university center and to describe their histopathological characteristics.

Material and Methods

Temporomandibular arthropathy cases with corresponding slides were selected from an oral and maxillofacial surgical pathology service. Cases of exclusively articular disc disease were not included.

Results

The mean age was 31.3 years with a predominance of females (69.7%). Of these diagnoses, 53.6% were unilateral condylar hyperplasia, 17.8% were bony ankylosis, 14.3% were degenerative joint disease, 10.7% were osteochondroma, and 3.6% were synovial chondromatosis. Condylar hyperplasia presented as thick fibrocartilage and cartilage nests in the cancellous bone. Bony ankylosis exhibited lamellar bone and nests of chondrocytes. Degenerative joint disease presented as an irregular layer of fibrocartilage with areas of clustered chondrocytes and calcified cartilage. Osteochondroma of the condyle exhibited hyaline cartilage and areas of new bone formation. Synovial chondromatosis presented as immature cartilaginous tissue and randomly arranged chondrocytes.

Conclusions

The pathological alterations verified in these arthropathies involved diseases that were predominantly proliferative, i.e., unilateral condylar hyperplasia, osteochondroma and synovial chondromatosis of the tumor or pseudotumor type and bony ankylosis associated with callus formation of the reparative type, and less frequent degenerative changes for which the disease is so named.

Key words:Temporomandibular joint, pathology, ankylosis, pathology, arthritis, degenerative, osteochondroma, chondromatosis, synovial.

Disk displacement, eccentric condylar position, osteoarthrosis - misnomers for variations of normality? Results and interpretations from an MRI study in two age cohorts

Background

Clinical decision-making and prognostic statements in individuals with manifest or suspected temporomandibular disorders (TMDs) may involve assessment of (a) the position of articular disc relative to the mandibular condyle, (b) the location of the condyle relative to the temporal joint surfaces, and (c) the depth of the glenoid fossa of the temporomandibular joints (TMJs). The aim of this study was twofold: (1) Determination of the prevalence of these variables in two representative population-based birth cohorts. (2) Reinterpretation of the clinical significance of the findings.

Methods

From existing magnetic resonance imaging (MRI) scans of the TMJs that had been taken in 2005 and 2006 from 72 subjects born between 1930 and 1932 and between 1950 and 1952, respectively, the condylar position at closed jaw was calculated as percentage displacement of the condyle from absolute centricity. By using the criteria introduced by Orsini et al. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 86:489-97, 1998), a textbook-like disc position at closed jaw was distinguished from an anterior location. TMJ morphology of the temporal joint surfaces was assessed at open jaw by measuring the depth of the glenoid fossa, using the method proposed by Muto et al. (J Oral Maxillofac Surg 52:1269-72, 1994).

Frequency distributions were recorded for the condylar and disc positions at closed jaw.

Student’s t-test with independent samples was used as test of significance to detect differences of condylar positions between the age cohorts (1930 vs. 1950) and the sexes. The significance levels were set at 5%. First, the results from the measurement of the age cohorts were compared without differentiation of sexes, i.e., age cohort 1930–1932 versus age cohort 1950–1952. Subsequently, the age cohorts were compared by sex, i.e., men in cohort 1930–1932 versus men in cohort 1950–1952, and women in cohort 1930–1932 women men in cohort 1950–1952.

Results

In both cohorts, condylar position was characterized by great variability. About 50% of the condyles were located centrically, while the other half was either in an anterior or in a posterior position. In both female cohorts, a posterior position predominated, whereas a centric position prevailed among men. Around 75% of the discs were positioned textbook-like, while the remaining forth was located anteriorly. Age had no statistically significant influence on condylar or on disc position. Conversely, comparison between the age groups revealed a statistically significant decrease of the depth of the glenoid fossa in both older cohorts. This age-dependent changes may be interpreted as flattening of the temporal joint surfaces.

Conclusions

We call for a re-interpretation of imaging findings because they may insinuate pathology which usually is not present. Instead, anterior or posterior positions of the mandibular condyle as well as an anterior location of the articular disc should be construed as a variation of normalcy. Likewise, flattening of articular surfaces of the TMJs may be considered as normal adaptive responses to increased loading, rather than pathological degenerative changes.

Trial registration

Not applicable.

Influence of orthodontic treatment on temporomandibular disorders. A systematic review

Objectives

The aim of this literature systematic review was to evaluate the possible association between malocclusions, orthodontic treatment and development of temporomandibular disorders. Material and Methods: A search was carried out on PubMed-Medline database from January 2000 to August 2013 using the keywords “orthodontics and temporomandibular disorders”, “orthodontics and facial pain” and “malocclusion and temporomandibular disorders”. Human studies included in the study were those assessing signs and symptoms of temporomandibular disorders in relation to orthodontic treatment.

Material and Methods

A search was carried out on PubMed-Medline database from January 2000 to August 2013 using the keywords “orthodontics and temporomandibular disorders”, “orthodontics and facial pain” and “malocclusion and temporomandibular disorders”. Human studies included in the study were those assessing signs and symptoms of temporomandibular disorders in relation to orthodontic treatment.

Results

The search strategy resulted in 61 articles. After selection according to the inclusion/exclusion criteria 9 articles qualified for the final analysis. The articles which linked orthodontics and development of temporomandibular disorders showed very discrepant results. Some indicated that orthodontic treatment could improve signs and symptoms of temporomandibular disorders, but none of them obtained statistically significant differences.

Conclusions

According to the authors examined, there is no evidence for a cause-effect relationship between orthodontic treatment and temporomandibular disorders, or that such treatment might improve or prevent them. More longitudinal studies are needed to verify any possible interrelationship.

Key words:Malocclusion and temporomandibular disorders, orthodontics and facial pain, orthodontics and temporomandibular disorders, temporomandibular disorders, temporomandibular dysfunction.